Board



Aug. 6, 1957 BOARD Re. 24,342

ELECTRICAL APPARATUS Original Filed Jan. 15, 1954 2 Sheets-Sheet 1INVENTOR.

BY 2M 2444, am n,

1957 R. BOARD ELECTRICAL APPARATUS Original Filed Jan. 15, 1954 2Shaets-She et 2 United States Patent OfiFice 7 Re. 24,342 Reissued Aug.6, 1957;

ELECTRICAL APPARATUS Ralph Board, Park Ridge, lll., assignor to SunElectric Corporation, Chicago, Ill., a corporation of Delaware OriginalNo. 2,703,376, dated March 1, 1955, Serial No. 404,162, January 15,1954. Application for reissue February 25, 1957, Serial No. 642,327

4 Claims. (Cl. 315-219) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates to improved electrical apparatus adapted foroperation from any one of a plurality of voltage sources, and moreparticularly to an improved timing light and a power supply thereforwhich is operable from any one of a plurality of voltage sources.

It is a principal object of this invention to provide means by whichelectrical apparatus may be operated from any one of a plurality ofinput voltages while maintaining predetermined output voltages andoperating characteristics.

It is a further object of this invention to provide an improved timinglight adapted for operation from any one of a plurality of known voltagesources. i

In the automotive art one of the most important adjustments of an enginerequired to produce optimum operating conditions involves thedetermination of the timing of spark ignition relative to enginerotation. This is necessary to initiate burning of the gasoline and airmixture within a particular cylinder at the proper point in the pistonmotion to insure maximum energy output.

To insure proper timing a device is provided by this invention which isprimarily energized from the automobiles electrical system and istriggered at predetermined intervals to emit a light flash. Thistriggering is accomplished by an electrical connection to a source ofextremely high voltage such as the spark voltage applied to onepreselected cylinder. It is a recent trend in automobile electricalsystems to use higher voltages whereby a more compact power pack may beutilized with improved starting characteristics. While heretofore allstandard automobiles in the United States have employed a six-volt powersupply, several manufacturers have currently developed a twelve-voltsystem. 7 a

It is, therefore, a further object of this invention to provide a timinglight and an improved power supply therefor which may be operated from aplurality of voltage sources, and especially from six and twelve-voltsources.

It is a furtherobject of this invention to provide an improvedelectrical device for operation from a plurality of selected voltageswhich will automatically adjust for proper operation from the appliedvoltage. I

It is another object of this invention to provide an improved timinglight for operation from six to twelve volt D. C. power sources.

It is an additional object of this invention to provide a simple, ruggeddevice adapted for use in automobile repair shops and the like whichwill automatically produce a predetermined output voltage for aplurality of known applied voltages. I

It is still another object of this invention to provide an electricaltiming light adapted for automatic operation from any one of a pluralityof known voltage sources whereby it will be safe and not subject toburn-out or other failure as a result of the application ofexcessvvoltages of contemplated values.

Further and additional objects of this invention will become manifestfrom a consideration of this description, the accompanying drawings, andthe appended claims.

In one form of this invention, an improved timing light is providedhaving a power supply which includes a relay connected across the inputterminals thereof sensitive to voltages in excess of a firstpredetermined value whereby the system may be operated from said firstpredetermined value to produce known output voltages while applica-'tion of a voltage source in excess of said predetermined value willcause actuation of the relay to alter the circuit of said timing lightto maintain the output voltages at the desired values. Moreparticularly,transfer switch means'is operated by said relay whereby anvassociatedtransformer is energized in such a manner that the num ber of turns inthe primary circuit will be proportional to the applied voltage andconsequently other portions of the circuit will be energized withpredetermined fixed voltages, irrespective of the applied voltage.

- For a more complete understanding of this invention, reference shouldbe made to the accompanying drawings, wherein Y Figure 1 is a plan viewof a timing light incorporating the novel features of this invention;

Fig. 2 is a plan view on alarger scale of the embodiment of Fig. 1 withportions thereof removed to illustrate the circuit elements containedtherein; and

Fig. 3 is a schematic diagram illustrating the electrical circuitrycontained within the embodiment of'Fig.

Referring now to the drawings, and more particularly to Figs. 1 and 2, agun-like timing light 10 is illustrated having a casing 11, preferablyof a phenolic material and including handle portions 12 and 14 andbarrel portion 16 extending outwardly therefrom. A lens 18 is secured atthe open end of barrel 16 whereby the light emitted by the device 10will becollimated into a substantially parallel beam. A pair of lowvoltage leads 20 and 22 and a high voltage trigger lead 24 are partiallyshown in Fig. 1 entering the handle 12 to supply electrical energy forthe timing light 10. When the apparatus is in use, the leads 20 and 22are connected to the battery terminals of the automobile under test andthe high voltage lead 24 is connected to one of the spark plug terminalsthereof. The low voltage leads provide a supply of energy to produce alight impulse each time the timing light is triggered throughlead 24.The light impulse is collirnated through lens 18 and directed toindicia, generally on the engine fly wheel, which indicates the exactposition of the engine at the instant the timing light is triggered. Asa result of the repetition rate of these impulses and the persistence ofhuman vision, the fly wheel appears to stop in the positioncorresponding to the firing instant.

As shown in Fig. 2, a vibrator or circuit interrupter 26 is containedwithin the handle portion 12, and a cylindrical condenser 28, preferablya large capacitance electrolytic condenser, is contained withinthehandle portion 14. These circuit elements are appropriately wiredthrough conductors 30 to a voltage-sensitive relay 32, a transformer 34,and a gas-filled flash tube 36 which comprises a light source. Theseelements constitute the basic electrical structure as will be describedin greater detail with respect to Fig. 3. y

The light source 36 comprises a glass tube 38 formed into a generally Ushape and having a pair of electrodes disposed in the legs thereof. Atrigger coil 40 is wound about the curved portion of the tube and isconnected to the high voltage conductor 24 which has a clip 42 connectedto the free end thereof adapted to engage a spark plug lead of an engineunder test. The system is designed to produce a voltage between theelectrodes of the gas tube 36 which will be insulficient to initiateionization of the gas and thus will not cause electrical dischargebetween the electrodes and consequent illumination. However,energization of the trigger coil 40 with a high voltage discharge fromthe associated'spark-plug will produce sufficient current by capacitivecoupling through the tube 36 to ionize the gas contained therein-andproduce a low impedance discharge path between .the electrodes andconsequently a high intensity light. The light thus produced will passthrough and be collimated by the convex lens 18. Clips 44 and 46 areprovided at the free ends of low voltage conductors and 22 forengagement with the battery terminals of an engine under test to providethe main source of power for the gas tube36.

For a more complete understanding of the electrical circuitry utilizedin the embodiment herein described, reference should be made to Fig. 3.Therein the low voltage clips '44 and 46 are shown connected throughconductors 20 and 22 to the voltage selecting relay 32. The contacts-ofrelay 32'are appropriately connected to the transformer 34 having twocenter tapped primaries and two associated secondaries. A rectifyingvibrator 26 is provided in series with the transformer primaries andsecondaries whereby the primary current is periodically interrupted andsecondary circuits correspondingly interrupted to produce a high voltageD. C. output. The secondaries of transformer 34 are connected toappropriate sections of condenser 28 to function as a voltage doublerand energy storage device. Light source 36 has its main electrodes 48and 50 connected to the terminals of a condenser 28 whereby the energystored therein is discharged through the gas filled envelope whenappropriately triggered by trigger coil 40. As explained above, triggercoil 40 is energized through high voltage conductor 24 and clip 42 whichis normally'connected to the lead associated with the first spark plugof an engine under test.

The particular system herein described is especially adapted foroperation from either six or twelve-volt supplies, which are the twosystems currently employed in American automobiles. The clips 44 and 46are connected to the battery terminals of an automobile under test. Ifthe subject automobile utilizes a 6 volt system the coil 52 will notactuate the associated contacts, while if the automobile under test hasa twelve-volt system the coil 52 of relay 32 will effect actuationof themovable transfer contacts 54 and 56 from the normally closed contacts 58and 60 to engage the respective normally open contacts 62 and 64.Generally the relay 32 is designed for actuation on about 9 volts toinsure proper operation at both preselected levels, The normally closedcontacts 58 and 60 are connected through conductors 66 and 68 to thecentertaps 70 and 72 of primary windings 71 and 73' of transformer 34.Thus, for voltages of the order of six volts applied to the terminals 44and 46 therrelay 32 is not actuated, and voltage is applied throughcenter taps 70 and 72 to only the halves 74 and 76 of the primarywindings of the'transformer 34. The other terminals of the normallyenergized halves 74 and 76 of the primary windings are connected tofixed contacts 78 and 80 within the vibrator 26 through conductors 94and 96. The vibrator 26 has a conducting vibratory reed 82 which isactuated by a coil 84 energized through conductor 86 which is, in turn,connected to conductor 68. The coil is thereby energized in parallelwith the half 76 of the primary winding of transformer 34. Thus, inoperation on voltages of the order of six volts, coil 84 of the vibrator26 is energized with a six-volt supply and effects motion of reed 82 tothe left in Fig. 3 to open the circuit between the reed and contact 88.The vibrator circuit may betraced as follows when the apparatus isenergized from a 6 volt supply: From clip 44 through conductor 20,movable transfer contact 56, normally closed contact 60, conductors 68and 86, vibrator coil 84, intermittent contact 88, reed 82 andconductors 98 and 22 to clip 46. Similarly the first primary circuitsmay be traced from clip 44 through conductor 20, contacts 56 and 60,conductor 68, primary section 76, conductor 96, intermittently engagedcontact 80, reed 82 and conductors 98 and 22 to clip 46. Thesecond-primary circuit may be traced from clip 44 through conductor 20,contacts 54 and 58, conductor 66, primary section 74, conductor 94,vibrator contact 73, reed 82 and conductors 98 and 22 to clip 46.

If a supply is connected between the input terminals 44 and 46 of theorder of twelve volts the relay coil 52 is actuated and the movablecontacts 54 and 56 move to engage the normally open contacts 62 and 64.This will apply a twelve-volt signal to the entire primary windings 71and 73 of transformer 34 through conductors 90 and 92 respectively. Thecircuit for primary windings 71 for 12 volt operation may be traced fromclip 44 through conductor 20, contacts 54 and 62, conductor 94), winding71, conductor 94, contact 78, reed 82 and conductors 98 and 22 to clip46. Thevihrator circuit may be traced from clip 44 through conductor 20,contacts 56 and 64, conductor 92, primary winding section 93, conductor86, vibrator coil 84, contact 88, reed 82, and conductors 98 and 22 toclip 46. Thus, when the system above described is operating on voltagesof the order of twelve volts the number of turns in the primary circuitsof transformer 34 is substantially doubled, thus producing the samevoltage in the secondary windings as is produced when the system isconnected to a six-volt supply and the relay 32 remains unactuated.(This is believed well understood from a consideration of simpletransformer theory.) When operating on a twelvevolt system coil 84 ofthe vibrator 26 continues to be operated through conductor 86 which isconnected to the center tap of the primary winding 73, and thus theprimary winding 73 functions as a voltage divider supplying a voltage atits center tap equal to one-half the applied voltage, or six volts, inthe embodiment herein described. The impedance of coil 84 must be highrelative to the impedance of primary 73.

Secondary winding 100, primary winding 71, secondary winding 102 andprimary winding 73 are all electromagnetically linked through iron core75. The orientation of the coils must be such that the fluxes and fluxchanges will be in aiding relationship. The voltage produced in each ofthese secondary windings is dependent upon the applied voltage andtheturns ratio of the transformer, as is well understood. In thisembodiment the voltage produced in each secondary winding is of theorder of 300 volts. The secondary has one terminal connected throughconductor 104 to a fixed contact 106 engageable by reed 82 within thevibrator 26, while the other terminal of the secondary winding 100 isconnected through conductor 108 to one electrode 48 of the gaseousdischarge tube 36. In a similar manner the secondary winding 102 has oneof its terminals connected to the fixed contact 110 engageable by reed82 within the vibrator 26 through conductor 112, while the otherterminal of the transformer secondary 102 is connected through conductor114 to the remaining electrode 50 within the discharge tube 36. Thefixed contacts 106 and 110 within the vibrator 26 are engageable by reed82 and complete circuits through said reed and conductor 116 to a commonconnection 118 between two sections 120 and 122 of the condenser 28.Each of the remaining terminals of the series combination of condensersections 120 and 122 is connected to one of the conductors 108 and 114.Thus, when the reed 82 is moved to the left in Fig. 3 under the magneticinfluence of coil 84, the contact 110 is engaged, whereby the secondarycircuit including winding 102 is completed and the condenser section 122receives an electrical charge. Similarly,

when the reed-82 returns to the right in Fig. 3 under its springtension, the fixed contact'106 is engaged thereby to complete thecircuit which includes transformer sec ondary 100 to produce anelectrical charge on the con denser section 120. In this embodiment,condensers 120, 122, 124 and 126 are incorporated into a singlecylindrical housing 28 and conveniently contained with handle section14. Other configurations may be em ployed. i l

The secondary winding 100 and 102 are so oriented that the voltagesproduced on condenser sections 120 and 122 will be in additive relation.Therefore, a resultant voltage will be produced on condenser section124, which is connected in parallel with the series combination ofcondenser sections 120 and 122, which is the sum of the voltagesappearing on these sections.

The charges accumulating on these condensers, and the rate of charge 'ofeach section will dependupon the relative capacitances thereof In thisembodiment, sections 120 and 122 are .3 mfd and section'124 is 1.6 mfd.

The manner in which the combination of transformer 34 and vibrator 26functions to produce a D. C. output should be understood. The fixedcontact 78 associated with the upper primary winding in transformer 34is disposed opposite the fixed contact 106, which is in circuit with theupper secondary winding 100. Therefore, each time the reed 82 invibrator 26 move to the right from the position in which it engagescontact 78 to the position in which it engages contact 106, thetransformer primary 70 will be de-energized to produce a collapsing fluxwithin the core structure, and the transformer secondary circuit will becompleted whereby this collapsing flux will produce a unilateral currenttherein. When the reed 82 moves to the left on the next half-cycleof'vibrator operation the secondary circuit will be opened prior to thecompletion of the primary circuit-that is, the reed 82 will leave thecontact 106 before engaging the primary circuit contact 78. Thus, therising flux resulting from the completion of the primary circuit throughcontact 78 will not produce a reverse current in the secondary as thatcircuit ha been previously opened by reed 82. The condenser 126 has arelatively small capacitance, functioning merely as a buffer condenserin parallel with the transformer secondary 100. It is "believed obviousthat all of the energy stored in condenser 124 is available for rapiddischarge between the electrodes 48 and 50 to produce a high intensityglow within the gaseous discharge tube 36 once a trigger impulse isreceived from the engine through trigger coil 40.

While the apparatus herein described is adapted for use on two knownvoltages, it is believed manifest that additional taps may be added tothe primary windings of the transformer 34 and an additional voltagesensitive device, such as relay 32, added corresponding to each tap onthe transformer whereby predetermined output characteristics will bemaintained for any number of known input voltages. For example, theparticular embodiment herein described is adapted to operate from sixand twelve volts. By adding a series winding to each of the primarywindings of transformer 34 and connecting the free terminals thereof tothe normally open con tacts of a transfer switch having a coil actuatedat a voltage about twelve volts, it is clear that a third possible inputvoltage is accommodated. Furthermore, although the power supply hereindescribed is illustrated in combination with an engine timing light andis especially useful in this combination, other uses will occur to oneskilled in the art, all of which are within the spirit and scope of thisinvention.

Furthermore, while this invention is particularly described inconnection with an embodiment employing a voltage doubler circuit,variou other power supplies could be employed such as simple vibratorself-rectifier circuits 6 or full or half wave tube rectifier circuitswithout'departing from the teaching of this invention.

While a particular embodiment of the invention has been shown, it willbe understood, of course, that the invention is not limited theretosince many modifications may be made and it is, therefore, contemplatedby the appended claims to cover any such modifications as fall withinthe true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired tobe secured by Letters Patent is:

1. Electrical apparatus for producing a timed visible impulseselectively from one of two known D. C. voltage source's comprisingrelay means having a coil and contact means actuatable thereby, inputterminals for connection to said voltage sources, said coil beingconnected to said input terminals, said contact means having a firstposition and a second position in accordance with the energization ofsaid actuating coil from said one and said other one, respectively, ofsaid voltage sources,- a transformer having two primary winding meansand a secondary winding, circuit interrupter means connected to beenergized from said voltage sources through said input terminals andhaving oscillating contacts in circuit with said terminals and saidprimary winding means for periodically interrupting energizing circuitstherefor, circuit means controlled by said contact means for completingan energizing circuit for said one primary winding means from said onesource and for said other primary winding means from said other source,respectively, in accordance with the energization of said actuatingcoil, [said interrupter means including further oscillating contactmeans in circuit with said secondary winding,] condenser means connectedin circuit with said secondary Winding [and said further oscillatingcontacts] for charging said condenser means during operation, andgas-filled light means having a pair of power electrodes connected tosaid condenser means and a trigger electrode to control said timedimpulses.

2. Electrical apparatus for producing a timed visible impulseselectively from one of two known D. C. voltage sources, one of whichhas a magnitude equal to substantially one-half of the other comprisingrelay means having a coil and contact means actuatable thereby, inputterminals for connection to said voltage sources, said coil beingconnected to said input terminals, said contact means having a firstposition corresponding to the unenergized condition of said coil and asecond position corresponding to energization of said coil with avoltage greater than a predetermined value intermediate the magnitude ofsaid two voltage sources, said coil being wound to effect said first andsaid second contact means positions when energized from said one andsaid other one, respectively, of said voltage sources, a transformerhaving a center-tapped primary winding and a secondary winding, acircuit interrupter means connected to be energized from said voltagesource through said terminals and having oscillating contacts in circuitwith said terminals and said primary winding for periodicallyinterrupting energizing circuits therefor, an operating coil foractuating said oscillating contacts, circuit means controlled by saidcontact means for completing an energizing circuit from said one sourceto the portion of said primary winding extending from the center tap toone end thereof and from said other source to said whole primarywinding, respectively, in accordance with the energization of saidactuating coil, said operating coil being connected across said primarywinding portion, [said interrupter means including further oscillatingcontact means in circuit with said secondary WindillgJ condenser meansconnected in circuit with said secondary winding [and said furtheroscillating contacts] for charging said condenser means duringoperation, and gasfilled light means having a pair of power electrodesconnected to said condenser means and a trigger electrode to controlsaid timed impulses.

3. Electrical apparatus for producing a predetermined potential outputselectively from one of two known D. C. voltage' sources one of whichhas a magnitude greater than the other comprising relay means having acoil and contact means actuatable thereby, input terminals forconnection to said terminal sources, said coil being connected to saidinput terminals, said contact means having a first positioncorresponding to the unenergized condition of said coil and a secondposition corresponding to energization of said coil with a voltagegreater than a predetermined value intermediate the magnitude of saidtwo voltage sources, said coil being wound to effect said first andsecond contact means positions when energized from said one and saidother one, respectively of said voltage sources, a transformer having atapped primary winding and a secondary winding, circuit interruptermeans connected to be energized from said voltage sources through saidterminals and having oscillating contacts in circuit with said terminalsand said primary winding for periodically interrupting energizingcircuits therefor, said interrupter means including an operating coilfor actuating said oscillating contacts, and circuit means controlled bysaid contact means for completing an energizing circuit from said onesource to a portion of said primary winding extending from the tap toone end thereof and from said other source to said whole primarywinding, respectively in accordance with the energization of saidactuating coil, said operating coil being connected acros said primarywinding portion, [said interrupter means including further oscillatingcontact means in circuit with said secondary winding] condenser meansconnected in circuit with said secondary winding [and said furtheroscillating contact means] for charging said condenser means duringoperation, and gas-filled light means having a pair of power electrodesconnected to said condenser means and a terminal electrode to controlsaid timed impulses.

4. Electrical apparatus for producing a predetermined potential outputselectively from one of two known D. C. voltage sources one of which hasa magnitude greater that the other comprising relay means having a coiland contact means actuable thereby, input terminals for connection tosaid terminal sources, said coil being connected to said inputterminals, said contact means having a first position corresponding tothe unenergized condition of said coil and a second positioncorresponding to energization of said coil with a voltage greater than apredetermined value intermediate the magnitude of said two voltagesources, said coil being wound to efiect said first and second contactmeans positions when energized from said one and said other one,respectively of said voltage sources, a transformer having a tappedprimary winding and a secondary winding, circuit interrupter meansconnected to be energized from said voltage sources through saidterminals and having oscillating contacts in circuit with said terminalsand said primary winding for periodically interrupting energizingcircuits therefor, said interrupter means including an operating coilfor actuating said oscillating contacts, and circuit means controlled bysaid contact means for completing an energizing circuit from said onesource to a portion of said primary winding extending from the tap toone end thereof and from said other source to said whole primarywinding, respectively in accordance with the energization of saidactuating coil, said operating coil being connected across said primarywinding portion.

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